One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,7)(3,6,4,8)(9,10)(11,18)(12,21)(13,16)(14,17)(15,20)(19,23)(22,24)(25,26)(27,35)(28,33)(29,31)(30,34)(32,37)(36,40)(38,39)(1,3,5,4)(2,6,7,8)(9,11)(10,15)(12,19)(13,22)(14,20)(16,23)(17,18)(21,24)(26,31)(27,28)(30,36)(32,33)(35,39)(37,38)(1,4,5,3)(2,6,7,8)(25,27)(26,32)(28,36)(29,37)(30,38)(31,35)(33,34)(39,40)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,23,18,24)(9,13,14,12)(10,16,17,21)(11,19,20,22)(15,24,18,23)(25,28,29,38)(26,33,31,39)(27,36,37,30)(32,34,35,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.